@Cheng Bin Zhang, certainly okay for them to find the 4th roommate (who wants to live with a stranger if they don't have to?)

Why bring up the most embarrassing part of their lives as a total stranger? 

I suppose since you're physically living there you can monitor this a little bit, but the cost/time/effort it will take to repair your broken laundry machines and worry about strangers being invited into your building to wash their clothes versus the amount of money you'll make on it is, in my opinion, not worth it.

I'm no stranger to small-town life, and it seems that turnover here is really, really low, which I like.  

option 1 is ok sell the trailer and contents to a stranger who will remove it and pay you for it. and rent out the lot to  someone who has a trailer looking for a space .  

So there is no way I was going to just give up all my trade secrets and knowledge that it took me years to get on my own. .so Some stranger walking up and asking me questions. 

People won't typically spend a lot of time helping a random stranger without any incentive -- so you need to provide that incentive. 

I don't know how well you know the guy but I wouldn't trust a strangers ability to screen tenants personally. 

Having a military background, I'm no stranger to hard work..

But does it also mean paying a stranger?